ok I searched a little bit for an answer to my question, but didn't really find anything. A simple question:

will my car (a FEH, so it does not "require" premium gas), get better gas mileage using premium gas (91+ octane) instead of regular gas (87 octane)?

I'm not asking about engine performance in terms of power. I know some cars require premium gas to get peak HP. I'm asking strictly about effect on mpg.

thanks